Treatment of hydrocarbons



Oct. 4, 1938. c. c. TOWNE TREATMENT OF HYDROCARBONS Filed Dec. 18, 1937Patented ct. 4, 1938 Charles G. Towne, Beacon, N. Y., assigner to 'litre'llexas Company, New York, N. Y., a corporation of Delaware ApplicationDecember 18, i937, Serial No. 130,555

Claims.

This invention relates to the manufacture of motor fuel and resins fromhydrocarbon oils, and has to do particularly with a process in whichhydrocarbon oils are converted into a. motor fuel naphtha havingantiknock properties, the extraction of this naphtha with a selectivesolvent to form an extract in which the aromatics and unsaturates are inconcentrated form, and the treatment of the resultant extract with apolymerizing agent to form a resin.

It has been known heretofore that cracked hydrocarbon distillates may betreated with an anv hydrous metallic halide catalyst to convertunsaturated and aromatic constituents thereof into w resins. However, inthe manufacture of resins from cracked distillates, such as commercialcracked gasolines, there is diiilculty in obtaining a resin ofsatisfactory yield and quality due to the unsatisfactory nature of theproduct treated, particularly with respect to the resin-formingvconstituents. An object of the present invention is to overcome thisdiiliculty.

In accordance with the present invention, the manufacture ofthe crackeddistillate is combined with the resin-forming operation to form aunitary process, whereby both an improved cracked distillate, from themotor fuel standpoint, is obtained as well as improved quality of resin.By practicing the invention with such a unitary process, it is possibleto obtain a high antiknock gasoline and good quality resin withoutsubstantial sacrice in yields. The improved results are due at least inpart, to improved methods of operation, including the extraction of thecracked distillate with a selective solvent,

whereby the resin-forming constituents are concentrated and separatedfrom the non-resinforming constituents which are usually of lowerantiknock value and may be recycled to the conversion operation.4Furthermore, the invention permits more drastic conversion conditionsto be maintained in the conversion operation due to the more eiiicientutilization of the normally gaseous hydrocarbons formed, comprisingretreatment of these gaseous hydrocarbons in the system to producepolymerization and reactions in the nature of gas reversion with thehydrocarbon oil undergoing conversion.

In practicing the invention, hydrocarbon oil charging'stock is subjectedto conversion conditions of temperature and pressure to form a motorAfuel fraction, such as cracked gasoline.

Charging stocks which may be treated may be any heavy oil suitable forthe conversion into lower boiling products, such as naphtha, gas

oil or reduced crude. The invention is particularly adapted to thereforming of naphtha in which a naphtha of low antiknock value is'subjected to conversion conditions to eiect transformation ofhydrocarbons of low antiknock 5 value into products of improvedantiknock value. Such naphthas include virgin naphthas as Well as heavyends of both virgin and cracked naphthas. The conversion operation maybe carried out utilizing the principle of gas reversion l0 wherein theoils are subjected to conversion conditions in the presence of normallygaseous hydrocarbons, which may be those developed and recycled in thesystem or all or in part those from an extraneous source, such asnatural or refinery l5 gases, or fractions thereof, such as propane orbutane or mixtures of propane and butane.

The cracked naphtha is subjected to treatment with a selective solventto eifect separation between the parains and the olefins and aro- 20matics. Solvents which may be used for this purpose are sulfur dioxide,ortho nitrodiphenyl ether, ortho nitrodiphenyl and para-aminodiphenyl. Iprefer to use liquid sulfur dioxide, according to the methods disclosedin U. S. Pat- 25 ents 911,553 and 1,526,665 of Edeleanu and U. S. Patent2,028,121 of Cottrell.

The extract separated from the cracked distillate is subjected to aresin-forming operation by treatment under suitable conditions with a 30metallic halide polymerizing agent, such as iron and zinc choride,preferably anhydrous aluminum chloride. The method disclosed in thepatents to Thomas and Hochwalt 1,836,629 and 1,982,707 may be used. 35

The invention will be further understood from the following descriptionwhich should be read in connection with the accompanying drawing showingdiagrammatically one form of apparatus for carrying out the process ofthe invention.

Referring to the drawing, the oil to be converted is charged by the pumpl through line 2, heat exchanger coils 3 and d, 4and line 5 to heatingcoil 'l located in a heater or furnace 8. In the heating coil l, the oilis subjected to con- 45 version conditions of temperature and pressurewhich may be about 800 to 1000 F. and 200 to 1000 pounds for crackinghigher boiling oils into lower boiling oils, or about 900 to 1100 F. and200 to 1000 pounds for naphtha reforming. The 50 conversion products aretransferred through the line 9 to a separator l0 in whichV any highboiling products, such as residuum; recycle stocks or other carbonaceousmaterial are separated and withdrawn from the lower portion thereof.'I'he 55 upper portion of the separator I0 may be cooled by the heatexchange coil 4, referred to heretofore. The uncondensed vapors andgases are passed from the upper portion of the separator I0 through thevapor line II to a fractionator I2. In this fractionator the crackeddistillate is condensed, with the aid of the cooling coil 3, andcollected in the lower portion thereof. The normally gaseoushydrocarbons uncondensed in the fractionator I2 are passed through theline I4 to a fractionator I5 .wherein the heavier constituents such asthe' C3 and C4 hydrocarbons are condensed and separated from the fixedgases which are released from the top of the fractionator through theline I1. The condensed normally gaseous hydrocarbons are withdrawnfromthe lower portion of the fractionator I5 by the pump I8 and recycledthrough the line I9 to the heating coil 1. The normally gaseoushydrocarbons recycled through the line I9 may be augmented by extraneousnatural or refinery gases introduced into the fractionator I5 throughthe line 20. The recycling of the normally gaseous hydrocarbons isoptional but is preferred because it has been found that much moredrastic conditions may be maintained in the heating coil by recyclingthese gases, whereby more extensive conversion may be effected and aproduct of improved antiknock value and increased unsaturate andaromatic content may be obtained.

The apparatus shown in the drawing is obviously diagrammatic and may bemodified to carry out any well known or preferred type of cracking orreforming operation. For example, reaction or soaking drums andadditional fractionators may be used. The apparatus is adapted for a`once-through operation such as commonly used in naphtha reforming.However, it may be modied to provide for carrying out recycle operationsof the clean or super-clean type. Also operations running to fuel oil orcoke are contemplated.

The converted naphtha collected in the bottom of the fractionator I2 iswithdrawn by the pump 22 and forced through line 23 to a mixer 25. Inthe line 23 is a cooling coil 26 located in an exchanger 21 throughwhich may be passed a refrigerating medium to cool the distillate to atemperature suitable for the subsequent extraction in the mixer 25. Suchtemperatures will depend upon the solvent used, for example with sulfurdioxide temperatures of about 40 F. or lower may be used. In the mixer25 the distillate is intimately contacted by a stirrer 28 with aselective solvent introduced through the line 29. The mixture is drawnfrom the bottom of the mixer through the pump 30 and line 3l, andintroduced into a settler 32 wherein the product is allowed to separateinto extract and rainate phases. If the solvent is of higher specificgravity than the oil, the extract phase will separate in the bottom ofthe separator 32, while the rainate, comprising the undissolved orparafin hydrocarbons, collects in the top of the settler. The raffinateis withdrawn through the pump 33 and line 34 to a stripper or still 35wherein the solvent is distilled off and passed through vaporline 36 andcondenser coil 31 to the tank 38. The raffinate freed ,from solvent isconducted from the bottom of the still 35 through the line 39 andl allor a portion thereof forced by pump 40 through di and line it to theheating coil 1. All or a portion of the raffinate may be by-passedthrough the line d2 to the accumulator 44. A portion oi? the ranate maybe passed through line 45 to 50 to a still 52. `rated from the extractby fractional distillation the polymerizer 41 to be used as a solvent ordiluent.

The extract comprising the solvent and dissolved hydrocarbons, includingolenns and aromatics is withdrawn from the bottom of the settler 32 bythe pump 49 and forced through line In this still the solvent issepaeither by release of pressure or by addition of heat, for example,by heating coil 53 located in the lower portion thereof. In case thesolvent is of lower boiling point than the hydrocarbon oil, as in thecase of SO2, the vapors of the solvent pass from the top of the stillthrough the vapor line 55 and condenser 56 to the accumulator 38. 'Ihesolvent may be withdrawn from the accumulator by the pump 51 andrecycled through the line 58 to the mixer 25. The still bottomscomprising the extracted hydrocarbons are withdrawn from the bottom ofthe still by the pump 60 and forced through the line 6I to thepolymerizer 41. It will be understood in case the solvent is of higherboiling point than the hydrocarbon extract that the hydrocarbons may berecovered as a distillate whiley the solvent will remain as the bottomsin the still 52. In any case, however, the ultimate disposition of thesolvent and the extract is intended to be the same.

In the polymerizing chamber 41 the hydrocarbons are contacted by meansof the stirrer B3 with a polymerizing catalyst which may be introducedthrough the line 64. The amount of catalyst is usually about 1 to 5% andpreferably about 3% by weight. A suitable diluent may be added to thepolymerizer, if desired, through the line S5 or naphtha'from line 45 maybe introduced thereto through the line 45, referred to heretofore. Thediluent, which may be naphtha or benzol or other solvent, is intended tobe added, if necessary, to maintain the proper consistency of theproducts in the polymerizer. The temperature in the polymerizer isusually maintained at about to 210 F. and preferably about 140 to F.This temperature may be maintained by a heating jacket surrounding thepolymerizlng chamber or any other suitable means. The reaction timerequired in the polymerizer is usually around 10 to 30 minutes althoughconsiderably longer periods of time, as much as 2 or 3 hours, may beused if necessary. 'I'he reaction products are withdrawn from the bottomof the polymerizer by the pump 61 and forced through the line 68 to asettler 10 wherein any sludge is allowed to settle out and is drawn offfrom the bottom thereof through the line 12. About 3 to 5% of sludge maysettle out in the settler 10 and may be treated for the separation of aresin, as will be described hereinafter in connection with the mainproduct.

A product substantially free from sludge is withdrawn from the settler10 through the pump 13 and line 14 to a still 15. In this still thematerials are contacted with an alkaline material, such as a 10%solution of sodium carbonate, introduced through the line 11 to effectneutralizatinon of acids and decomposition of the metallic halidehydrocarbon compounds. Steam may be introduced into the lower portion ofthe still through the line 'It to accelerate decomposition and to effectdistillation of ,low boiling hydrocarbons and diluent. The mixture ofresinous material and aqueous salt solutionris withdrawn from the bottomof the still through the pump 80 and line ai to settling chamber 82wherein separation is allowed to take place and the aqueous thefractionator 88.

neutralization products withdrawn through the line 84 and the resinthrough the line 85.

The vapors are removed from the top of the still 15 through vapor line81 and introduced into In this fractionator the higher boilinghydrocarbons or diluent are condensed and withdrawn from the lowerportion thereof through the line 89 by pump 90. A portion or all of thismaterial may be recycled through the line 9| and line 92 to thepolymerizer 63, or through the line and lines 4l and i9 to the heatingcoil l. The uncondensed vapors are conducted from the top of thefractionator 88 through the vapor line 93 and condenser 94 to anaccumulator 44. The product collected in the accumulator 44 isordinarily highly aromatic and may contain a large proportion of benzoland toluol. A portion of this product may be recycled to the polymerizeras a diluent, if desired, or may be combined, all or in part, inaccumulator 49 with the naphtha from line 42, referred to heretofore, toform a high antiknock motor fuel product. A

The resin withdrawn from the settler 82 may be ready for use, althoughordinarily it is desirable to mix therewith a suitable thinner or drier.A nished product, such as one suitable for use as a protective coating,may contain about 25% vof a thinner, such as naphtha. The resin is alight colored product and is suitable for use in paints and varnishes.

As an example of the operation of the invention, a straight run naphthaof about 40 octane value is subjectedvto reforming at a. temperature ofabout 1050" F. and under a pressure of about 1000 pounds. The reformednaphtha is separated and the normally gaseous hydrocarbons comprising C3hydrocarbons and lighter and all or a portion of the C4 hydrocarbons,are subjected to further fractionation under about 800 pounds pressureto separate the xed gases, including the methane and hydrogen and all ora portlonof the C2 hydrocarbons. The heavier normally gaseoushydrocarbons are recycled to the reforming operation. The amount ofrecycle gases is approximately 25% of the fresh charge. About 85l to 90%of reformed naphtha of about 75 to 80 octane is obtained 'I'he reformednaphtha is lsubjected to solvent extraction with liquid SOz at about 40F. Using a ratio of solvent to naphtha of about 1:1, an extract yield ofabout 40%, and a raillnate yield of about 60%v are obtained. A portionof the ramnate, amounting to about 25% of the furnace charge, isrecycled to the reforming operation. The extract is treated with about3% by weight of the anhydrous aluminum chloride at about to 160 F. forabout 2.0 minutes. 'Ihe resulting product, after the separationbfsludge, is treated with an aqueous solution of 10% sodium carbonate insuflcient amount to elfect neutralization and the mixture is thendistilled. About 70 to75% of a light oil, based on the naphtha extractand consisting largely of benzol and toluol is recovered as a distillatewhich is combined with the reformed naphtha. product to form a nishedmotor fuel. A resin is separated from the undistilled mixture,comprising resin and salt solution. The resin amounts to about 25% ofthe mixture after dehydation.

. The present invention has the advantage of permitting deep cracking orreforming of the oil,

whereby naphtha of high antiknock value and containing a largeproportion of unsaturates and aromatics is obtained. Whereas normallyconsiderable loss would be experienced as a result of gas formationduring the drastic conversion operations, according to the presentinvention, these gases are largely converted into naphtha products ofunsaturated or aromatic character. The naphtha produced is highlysatisfactory for the production of resins and also affords a means ofproducing a high yield of relatively pure aromatic compounds, such asbenzol and toluol.

Obviously many modifications and variations of the invention, ashereinbefore set forth, may be made without departing from the spiritand scope thereof and therefore only such limitations should be imposedas are indicated in the appended claims.

I claim:

l. The process which comprises subjecting hydrocarbon oil to a crackingoperation to convert higher boiling oils into lower boiling oils of theclass of gasoline, separating from the cracked products a crackednaphtha, extracting said naphtha with a solvent having selective solventproperties for unsaturated and aromatic' hydrocarbons, separating anextract containing said aromatic and unsaturated hydrocarbons inconcentrated form, and treating said extract With an anhydrous metallichalide polymerizing agent to produce a synthetic resin.

2. The process which comprises subjecting hydrocarbon oil and normallygaseous hydrocarbons to conversion conditions under temperaturessufcently high to produce gasoline hydrocarbons, separating from thereaction products a naphtha fraction containing said gasolinehydrocarbons, extracting said naphtha fraction with a selective solventthereby producing an extract rich in oleiinic and aromatic hydrocarbons,and treating said extract with an anhydrous metallic halide polymerizingagent to produce a synthetic resin.

3. The process which comprises subjecting a naphtha of low antiknockvalue to reforming temperatures whereby hydrocarbons of low antiknockvalue aretransformed into hydrocarbons of high antiknock value,extracting the reformed naphtha with a selective solvent to separateoleflnic and aromatic hydrocarbons from paraf,

nic hydrocarbons, separating an extract containing olens and aromaticsin concentrated form, and treating said extract with an anhydrousmetallic halide polymerizing agent to produce a synthetic resin.

4. The process which comprises subjecting a naphtha of low antiknockvalue in the presence of normally gaseous hydrocarbons to reformingtemperatures suiciently high to eiect transformation vof hydrocarbons oflow antiknock value into products of high antiknock value, includingsubstantial amounts of unsaturates and aromatics, subjecting thereformed naphtha to solvent extraction with a selective solvent adaptedto effect substantial separation of unsaturates and aromatics fromparaiins, separating an extract fraction containing 'the unsaturates andaromatics in concentrated form, and treating said fraction with ananhydrous metallic halide polymerizing agent to produce a resin.

5. A process according to claim 4 in which the polymerizing agent isaluminum chloride.

CHARLESC. TOWNE.

